1. Field of the Invention
The present invention relates generally to motion picture special effects generation and control systems and, more particularly, to a system for simulating an effect such as an earthquake including a control sub-channel incorporated into an existing motion picture film format which produces multi-function analog and digital control signals.
2. Description of the Prior Art
A number of techniques have been proposed or utilized to produce special effects for motion picture theater audiences in addition to the conventional audio sound track. in those systems designed to produce a physical effect on the theater audience, the approach has heretofore been to provide a direct physical stimulus in the form of odors as represented, for example, by U.S. Pat. No. 1,749,187 or physical movement cued to the visual presentations such as vibrating seats or the like, as represented, for example, by U.S. Pat. No. 2,861,806. It will be appreciated that such systems require extensive modification of the theater in which they are installed or the theater must be specially built for such systems, such as with a vibrating floor or seats.
Some of these systems have been designed to be cued from special control tracks or notches on the motion picture film. Other systems have utilized analog control signals which are frequency multiplexed onto a magnetic or optical track such as, for example, the system described in U.S. Pat. No. 2,714,633. Typically, these special effects control systems require special reproduction equipment which is not compatible with ordinary motion picture projection equipment.
Thus, in the past, producing physical sensations in a theater audience has required elaborate theater equipment for direct physical stimulation. Additionally, such equipment was typically specially designed and incompatible with conventional motion picture film formats. There has therefore been a need for special effects system which could produce physical sensations in an audience in a conventional theater when desired and still be compatible with conventional film formats and projecting equipment. The present invention satisfies that need.